Parts for the Electric Sutra

Well, that’s been a weird old week two weeks1I mean, the first week was weird, and then the second week in self-isolation was even weirder. The fact that one of the triggers for self-isolation is “a persistent cough” is an issue with three small children, because at this time of year at least one of them will always have a cough. I digress.

However, rather than ponder the generation-defining crisis that Covid-19 is rapidly becoming2actually, if you’ll permit me a second digression; I am struggling with that name. It somehow lodged in my mind as Corvid-19, and now I’m left with the enduring mental image that the world has been reduced to a knee-jerking panic by a single grumpy crow, let’s indulge in some collective head-in-the-sand-ing and talk a bit more about the project to electrify my touring bike.

One of the benefits of working from home all week is that I’ve been in to receive the various parcels of parts. I’ll use this post to talk through what and why, and the next one to cover the build3Which, between you and me, I’ve already started. Protip: removing a five-year-old bottom bracket is not a trivial task…. As a reminder, here’s the previous post explaining what we’re doing.

We’ll come to the motor and battery at the end, but both bits have some bearing on the other things I’ve gone with, so let’s talk through those first.

Why these parts?

One of the things to note is that the display I’ve chosen is enormous (so we’re after a handlebar with space for it), and that it’s good practice with a crank motor to use the gears to ensure it’s not grinding away too hard. That means swapping out my ever-reliable bar-end gear shifter (which I have a tendency to set and then ignore, treating the bike more as an adjustable single-speed…) for something a little more under-the-thumb.

I’ve had problems this winter with my cable-actuated disc brakes freezing open, which is sufficiently unsettling that I’d like to avoid it again. Cable discs are also more of a faff to keep in perfect adjustment, so I leave it until I’m bottoming the lever against the bar, which isn’t great for safety in Glasgow’s somewhat unpredictable rush hour traffic… Hydraulic disc brakes would remove both those annoyances, but I’m currently running shallow drop handlebars, and I have no experience with road-lever hydraulics.

Switching to a flat bar would mean I can use Shimano Deore brakes (and the matching Deore trigger shifters), which are both excellent and great value. However, I still want to keep a lot of hand positions, including at least one with is a bit more aero, for those long slogs into a headwind.

My current Shimano 1×9 drivetrain has been fine, so a pretty straight replacement with whatever’s on offer at the time will do there.

With that as a vague set of intentions, here’s what I went for.

The non-motor parts

(I’ve given weights for the big stuff, but if you’re concerned about the weight of a brake lever, you’re on the wrong blog.)

Surly Moloko Bar

Starting off, then, 750g of gloriously weird handlebar from Surly; the Moloko. Surly stuff isn’t cheap, but it is very good (this bike already carries their front rack, and it’s as tough a lump of steel as you’ll find). The hope here is for lots of comfy hand positions, plenty of space to mount the motor display plus my Garmin, and a more aerodynamic grip using the two horns in the middle.

Next up is the Shimano Deore hydraulic brakes. This was a pre-bled “ready to go” kit, so I’m slightly disturbed to see that the rear lever is separate from the hose. I’m rubbish at bleeding brakes. Still, at least Shimano hydraulic oil doesn’t melt your hands.

And the shifters. We’re going for nine-speed rather than ten, because I felt a slightly chunkier chain would be a Good Thing. This is therefore an older model of Deore shifter, which means it was reduced. Result. Also a full length gear-cable housing. Because the motor snuggles up under the bottom bracket, if your bike (like mine) runs cables under there, they need to move. Full housing means I can ignore the cable stops on the frame and just run straight from the levers to the derailleur.

Standard Deore derailleur, with long cage for the big cassette. And a cheap and cheerful chain.

Cassette. Slightly out of range at the top end (36T) for the derailleur spec, but other reviewers have said it works fine.

Haribo. Because I ordered most of this stuff from Wiggle…


On to the more fun stuff. In the last post, I said I was going with the torque-sensing Tongsheng TSDZ2 over the cadence-sensing Bafang. The most powerful UK-legal version of that is the 48V 250W model (there’s some debate over whether this is functionally the same as the 36V 250W model, but I didn’t fancy over-volting my new motor to test that theory).

There are two options for buying this stuff. The first is going direct to sellers in China via Amazon marketplace, eBay or AliExpress. That’s a lot cheaper4mainly because all of them say that they’ll pay the import duties and taxes for you. I leave the calculation of the likelihood of that as an exercise for the reader…, but you’ll be waiting longer for delivery, and if you have a warranty issue you’re dealing with an entity that may or may not be a single person in a shed on the far side of the world.

Or, you can go to the UK re-seller Woosh Bikes. Delivery is a couple of days, the support is from the UK and really quick (I had responses to a couple of dimension questions I sent within an hour or so), you can buy matching motor/battery sets (so the connections are just plug together, rather than crimping on connectors), and all the kit comes with a load of kitemark stickers that suggests it meets the UK regulations.

We all know (and Woosh Bikes don’t hide) that it’s exactly the same stuff. And the Woosh option at £659 total worked out about £130 more expensive than the cheapest on AliExpress. However, for my first attempt at electrification, I’m happy to pay for a bit of peace of mind, ease of warranty, and what turned out to be a really good set of installation instructions from Woosh (with photos and idiot-proof descriptions like “plug the yellow connectors together”).

Here’s the motor. Turns out my kitchen scales couldn’t cope with more than 3.5kg, so based on the bathroom scales5and the tried and tested [me holding motor] – [me without motor]=[motor] + [a somewhat worrying level of uncertainty from the poor quality of my bathroom scales] I reckon it’s about 3.7kg. The photo above shows the motor on its side; the bit on the left sits beneath your bottom bracket.

Given that weight, you won’t be surprised to learn that it’s reassuringly solid. That case is metal, not plastic, and the whole thing feels well-made. It’s also user-serviceable, which is a massive bonus over the Shimano and Bosch motors (although there is a small security seal from Woosh saying the one-year warranty is void is you open it up, which is fair enough).

This is a 12AH Hailong downtube-mounted battery, that slides in and out of a mounting plate that stays permanently attached to the bike. Again, it’s liberally festooned with stickers saying “do not eat” and other vital warnings. 3.4kg.

I had originally planned to go with a much smaller-capacity 36V battery (which is therefore physically smaller and lighter), thinking that I might as well just match the range needed for my commute, plus a safety margin. However, when I realised that the 48V motor was UK-legal, I also discovered that you don’t get small 48V batteries—you need a lot more cells within the battery to get up to that voltage, and that takes more space.

I think the trade is worth it. Higher voltage means more power and, weirdly, more efficiency as well (so you can go up steeper things faster for longer).

The other two bits I forgot to take photos of, so here’s some crops from assembly photos. The surprisingly large screen:

and the remote on the handlebars:

That remote is the only bit of the entire kit that feels cheap. The upside-down question mark is a bit ¿qué? and the switch behind the + button at the top is too far to the left, so the right-hand side of the button is very spongey. Still works, although might be a challenge in gloves.

Next steps

I’ve been chipping away at assembly over the last week (with most of that time spend on “persuading” the old bits of my bike to come apart…), and last night I finally connected everything together and ran power through the kit. The screen lit up and nothing caught fire, so I’m counting that as a success.

Stay tuned…


Add Yours →

Following your progress with this project is part of my self isolation sanity strategy, keep the posts coming . I think you’ll love the new bars. I went for similar Crazy Bars which are just so comfortable and seem no less efficient than drops.

Very nearly went for the crazy bars, but decided the double loop of the Moloko would be perfect for the big screen, plus lights and Garmin above.

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